This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
Fourth generation (4G) wireless mobile telecommunications technology, also known as Long Term Evolution (LTE) technology, was designed to provide high capacity mobile multimedia with high data rates particularly for human interaction. Next generation or fifth generation (5G) technology is intended to be used not only for human interaction, but also for machine type communications in so-called Internet of Things (IoT) networks.
While 5G networks are intended to enable massive IoT services (e.g., very large numbers of limited capacity devices) and mission-critical IoT services (e.g., requiring high reliability), improvements over legacy mobile communication services are supported in the form of enhanced mobile broadband (eMBB) services intended to provide improved wireless Internet access for mobile devices.
Security during mobility of user equipment or UE (such as, for example, a mobile terminal or subscriber) between two networks (i.e., intersystem mobility) is an important consideration. For example, initial Non-Access Stratum (NAS) messages, e.g., registration messages, between the UE and a network are integrity protected by the UE if there is a current NAS security context in the UE that is valid and accepted by the network.
Today, in the scenario where the UE is moving between networks, e.g., interworking between a 4G network and 5G network, adequate integrity verification is not yet defined.